I. Field of the Invention
This invention relates generally to the formation of plural printed documents in stacked relationship for handling and mailing. More particularly, the invention pertains to a method and apparatus for securing stacked plural printed documents by utilizing adhesive tabs which wrap around the sides of the stacked plural printed documents and glue beads interposed among the stacked plural printed documents for maintaining the integrity of the stack during handling and mailing.
II. Background of the Invention
Magazines printed for distribution via the United States Postal Service (USPS) are typically addressed at the facility where the individual components are collated and bound to produce the magazine. The postage represents a significant portion of the overall production cost. The USPS regulations include a number of options which allow the publisher to reduce postage costs. These reductions are the driving force behind the magazine packaging which occurs at the printing plant. One such option relates to so called "firm packages" in which a plurality of documents such as magazines, catalogs, etc. are to be delivered to a single address.
In a typical magazine production process the magazine signatures are collated and then bound together. The complete magazines are then addressed either inline with the collating and binding machinery or offline on an independent mail labeling line. After the magazines are labeled, they are stacked and then bound into packages. The package forming operation typically employs machinery which cross-ties and/or shrinkwraps the stack of magazines.
The formation of the packages is the point in the process when most of the postage cost reduction options are available. In the simplest case, the packages would be formed into constant size stacks with the address labels for the magazines in no particular order. This leaves the entire sorting effort to the post office and results in no discount. The discounts occur when the magazines are presorted according to the USPS regulations. The current practice results in varying size packages which include magazines that are destined for a particular city or zip code destination. At the finest presort level, magazines which are destined for the same address are packaged together. Such packages are referred to as "firm packages" by USPS definition. However, due to limitations with the existing packaging methods of cross-tying or shrink wrapping, small-count firm packages are not typically produced.
The usual minimum package size per USPS regulations is six magazines for second class mail, although USPS regulations can be met with smaller "firm" packages. The existing packaging equipment is only capable of forming packages of six or more at typical line speeds. The formation of firm packages of two to five magazines requires a maximum cycle rate which exceeds the current state of the art for stacking, cross-tying, and shrink wrapping equipment. Small-count packages also pose a problem for cross-tying or shrink wrapping because the small stack tends to curl up as the shrink wrap or cross-tie straps are applied.
In some instances, small-count firm packages are produced by slowing down the binding line. This results in cost increases for labor and binding line utilization, which quickly can negate any postage cost avoidance. The problem of curling is still present at the lower speeds.
An alternative application for the formation of packages occurs when a publisher wishes to mail some or all of their magazines with a renewal card, bill, advertising or editorial supplements referred to as "allowable enclosures" or "onserts". In this case a wrapper, envelope or polybag is used to contain the magazine onserts and the magazine. Polybags are typically applied offline because the polybagging process is slower than typical line speeds and it does not allow intermittent application of the polybag.
Therefore what is needed is a method and apparatus which can operate at typical line speed to form small-count firm packages and does not cause curling of the items to be packaged. The present invention forms packages, by the automated application of tabs, which are applied to opposite sides of a stack of plural printed documents. The tabs wrap around opposed edges of the stack and contact the top and bottom book in the stack. The tabs are held in place by a peelable adhesive. Small beads of peelable adhesive may also be placed between the magazines or onserts in the stack to prevent skewing or slipping of the magazines or onserts during handling and/or mailing.